1. Field of the Invention
The present invention relates to a solar cell and a manufacturing method thereof. More particularly, the present invention relates to a solar cell with a better photoelectric conversion efficiency, and a manufacturing method thereof.
2. Description of Related Art
In recent years, an environmental protection consciousness is highly aroused. To resolve a problem of petroleum energy shortage, research of renewable energy is highlighted, in which solar cells become a focus of attention in development of the renewable energy.
In the solar cell, when sunlight irradiates a P-N diode, photons can enter the P-N diode to generate photocurrent, and the photocurrent is output by two electrodes of the P-N diode to generate voltage.
In a method for manufacturing a general solar cell, an N-type doped layer can be formed on a P-type silicon substrate through a deposition process, and then a front contact and a back contact can be formed at two sides of the P-type silicon substrate, wherein the front contact is defined as an electrode close to a light incident surface, and the back contact is defined as an electrode located apart from the light incident surface. Since the front contact is generally formed by a metal material, a part of the N-type doped layer is probably shielded by the opaque front contact, so that a photon absorption rate of the N-type doped layer is reduced. Moreover, a defect generated due to a contact between the metal material front contact and the N-type doped layer can probably lead to a merging phenomenon of electrons and holes passing through the contact area, so that an output of the photocurrent is limited.
Moreover, to ameliorate the light-shielding problem, the front contact is generally designed to be an interdigital structure with a narrow linewidth, though such structure design can lead to a problem of excessive series resistance, so that the output of the photocurrent is reduced. Therefore, a photoelectric conversion efficiency of the solar cell cannot be effectively improved according to the above design.